Measuring Grain Junction Angles in Discretized Microstructures

Abstract

Grain junction angles control microstructural morphology and evolution, but because they are difficult to measure, they are reported rarely. We have developed a method, based on the optimization of the Pearson’s correlation coefficient, to measure grain junction angles in planar discretized microstructures without converting or remeshing the original data. We find that the grain junction angle distribution of equiaxed, relatively isotropic, three-dimensional (3D) microstructures is a Gaussian distribution centered about 120 deg, with a larger width than predicted primarily because of boundary energy anisotropy. Short boundary segments, which occur primarily in sections of 3D microstructures, cause anomalous peaks in the grain junction angle distribution that provide a marker for sample dimensionality. The grain junction angle distribution is a characterization metric for digitized microstructures, revealing the effects of grain boundary energy anisotropy, simulation parameters, and dimensionality.